Ophthalmic cannula insertion tool and method

ABSTRACT

A cannula insertion tool having a needle movable between a retracted position and an extended position. In some embodiments, the needle can be retracted within the periphery of a handle of the insertion tool when not in use to protect the needle. When the needle is needed for surgical use, the needle can be extended at least partially beyond the outer periphery of the handle. The needle can be coupled to a slide movable relative to the handle between the retracted position and the extended position. The slide can be secured in each position to prevent unintentional movement of the slide. A cannula can be positioned on the needle when the needle is in the retracted position, and can be retained upon the needle by a member extending toward the cannula.

FIELD OF THE INVENTION

Embodiments of the invention relate to aspects of improvedtrocar-cannula devices for use in surgery of the posterior segment ofthe eye.

BACKGROUND OF THE INVENTION

A trocar-cannula is a surgical instrument. It can be used to drain fluidfrom a body cavity, introduce fluids into the body cavity, and insert atool into the body cavity to perform surgical functions. Thetrocar-cannula is often comprised of two principal parts: (1) a hollowtube or cannula and (2) a puncturing member referred to as an obturatoror trocar. The cannula is inserted through the wall of the body cavitywith the assistance of the trocar passed through the cannula.

A trocar-cannula may be used in cardiovascular surgery, laparoscopicsurgery, arthroscopic surgery, and intraocular surgery. In intraocularsurgery, for exanple, a trocar-cannula is often used to obtain access tothe posterior-segment of the eye (area behind the lens). Typically, acannula is positioned on a needle of a trocar for insertion into theeye. The needle is used to penetrate the eye and insert the cannula.Upon insertion of the cannula, the trocar can be removed from the eyewhile the cannula remains inserted in the eye.

SUMMARY OF THE INVENTION

Conventional ophthalmic trocars generally have a handle and a needlefixed to the handle. The needle of some conventional trocars can beprotected by a cap that can be placed over the needle. However, sincethe cap can be separated from the trocar, the cap can be misplaced orotherwise prematurely removed from a position shielding the needle,thereby exposing the needle at undesirable times.

Some embodiments of the present invention provide a trocar having aneedle that is protectable without the need for additional parts thatcan be separated from the trocar. In some embodiments, an ophthalmictrocar having a retractable needle is provided, wherein the needle canbe retracted to a protected position within the periphery of a handlewhen not in use. When the needle is needed for surgical use, the needlecan be extended at least partially beyond the outer periphery of thehandle.

In some embodiments, the needle is coupled to a slide that is movablerelative the handle between a retracted position and an extendedposition. In some cases, the slide can be secured in either or bothpositions. In the retracted position for example, the slide can beselectively secured to prevent unintentional movement of the slide tothe extended position. In the extended position for example, the slidecan be secured to prevent the slide from moving relative the handleduring use of the trocar.

In some embodiments, the trocar has a cannula positioned on the needlewhen the needle is in the retracted position, and has a memberpositioned to prevent the cannula from inadvertently disengaging theneedle in the retracted position.

These and other aspects of the embodiments of the invention, togetherwith the organization and operation thereof, will become apparent fromthe following detailed description when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a trocar-cannula according to anembodiment of the present invention, wherein the needle of the trocar isshown in a retracted position with a cannula positioned on the needle.

FIG. 2 is a perspective view of the trocar-cannula shown in FIG. 1,wherein the needle of the trocar is shown in an extended position.

FIG. 3 is a perspective view of the handle of the trocar shown in FIG.1.

FIG. 4 is a perspective view of the slide of the trocar shown in FIG. 1.

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the following drawings.The invention is capable of other embodiments and of being practiced orof being carried out in various ways. Also, it is to be understood thatthe phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limited. Phraseology andterminology used herein with reference to device or element orientation(such as, for example, terms like “front”, “back”, “up”, “down”, “top”,“bottom”, and the like) are only used to simplify description of thepresent invention, and do not alone indicate or imply that the device orelement referred to must have a particular orientation. Also, the use of“including,” “comprising,” or “having” and variations thereof is meantto encompass the items listed thereafter and equivalents thereof as wellas additional items. The terms “mounted,” “connected,” and “coupled” areused broadly and encompass both direct and indirect mounting, connectingand coupling. Further, “connected” and “coupled” are not restricted tophysical or mechanical connections or couplings.

DETAILED DESCRIPTION

With reference to FIG. 1, there is shown an ophthalmic trocar-cannulaassembly 10 having a trocar 12 and a cannula 14. The trocar 12 includesa handle 16, a slide 18 moveable within an elongated aperture 20 of thehandle 16, and a needle 22 coupled to the slide 18. The cannula 14 isadapted to be received on the needle 22 as shown in FIGS. 1 and 2 forinsertion with the needle 22 into an eye.

The handle 16 in the illustrated embodiment includes a main body portion24 and two arms 26 extending from an end 28 of the main body portion 24.The arms 26 can be integral with the main body portion 24 or can beseparate elements attached to the main body portion in any suitablemanner. Also, the arms 26 can be cantilevered from the main body portion24 and extend from the end 28 of the main body portion in a longitudinaldirection (e.g., wherein the ophthalmic trocar-cannula assembly 10 iselongated to define a longitudinal direction of the assembly 10). In theillustrated embodiment, the arms 26 at least partially define theelongated aperture 20 extending in the longitudinal direction.

With continued reference to FIGS. 1-4, the arms 26 each have a rib 30that extends along the arm 26 in the longitudinal direction. The ribs 30extend substantially the entire length of the arms 26, and extend froman inner surface 32 of the arms 26 into the elongated aperture 20. Inother embodiments, the ribs 30 extend along less than the entire lengthof the arms 26, depending at least in part upon the desired range ofmotion of the slide 18 and upon the location of projections and recessesof the slide 18 and arms 26 (described in greater detail below). Theribs 30 can also be recessed relative to a top surface 34 and a bottomsurface 36 of the handle 16 as shown in FIGS. 1-4.

As illustrated in FIG. 3, the inner longitudinally extending edge 38 ofeach rib 30 is interrupted by one or more recesses or projections. Theseprojections and recesses help to retain the slide 18 and/or cannula 14in desired positions with respect to the handle 16. For example, a pairof recesses 40, 42 can extend into each rib 30 on either side of aprojection 44 that extends from the rib 30. Each rib 30 can also extendlongitudinally away from a location 45 adjacent the recesses 40, 42. Oneof the recesses 40 in each rib 30 illustrated in FIG. 1-4 is defined bythe projection 44 and another part of the rib 30, and engages a portionof the slide 18 when the slide 18 is in the retracted position (FIG. 1).Recess 40 receives one or more projections 46 on the slide 18 when theslide 18 is in the retracted position to prevent unintended movement ofthe slide 18 from the retracted position.

The recesses 40, 42 and the projection 44 are positioned along a portionof the rib 30 corresponding to the retracted position of the slide 18.In the illustrated embodiment, the recesses 40, 42 are located at amid-portion of each arm 26. However, in other embodiments, the recesses40, 42 can be located in other positions along the arms 26 (e.g., suchas where the arms 26 engage the slide 18 at different longitudinalpositions of the slide 18).

With the exception of the recesses 40, 42 described above, each rib 30can have a substantially uniform cross-sectional shape along any part orall of the rib 30. With reference again to FIG. 3, recess 42 cutstransversely into the rib 30 and extends along the rib 30 in thelongitudinal direction for a relatively short distance. A ramped surface50 extends from the recess 42 to provide a transition between the recess42 and an adjacent portion of the rib 30 having projection 44. Theprojection 44 only extends a relatively short distance in thelongitudinal direction before being interrupted by the other recess 40.The projection 44 transitions into the recess 40 along a ramped surface52. This recess 40 is approximately as deep as the recess 42 on theopposite side of the projection 44, although the recesses 40, 42 canhave different depths in other embodiments. This remainder of the rib 30(extending from location 45) can extend into the elongated aperture 20substantially the same distance as the projection 44, or can extend to agreater or lesser distance in other embodiments.

As mentioned above, recess 40 is dimensioned and positioned to receivethe projection 46 of the slide 18. When the projection 46 of the slide18 is received within the recess 40, engagement between the projection46 and the recess 40 prevents movement of the slide 18 from theretracted position. The ramped transition 52 between the recess 40 andthe adjacent projection 44 helps to disengage the slide 18 from theretracted position upon application of a sufficient force to elasticallydeform the arms 26 of the handle 16.

As shown in FIGS. 1 and 3, an additional projection 54 can extend fromone or more of the arms 26 to block the cannula 14 from inadvertentremoval or from falling off the needle 22 when the needle 22 is in theretracted position. The projection(s) 54 can be located on the ribs 30of the handle 16, or can extend from any other portion of the handle 16to a location in which the cannula 14 is blocked from moving off theneedle 22 in the retracted position. In the illustrated embodiment, forexample, each projection 54 is positioned further toward the distal end48 of each arm 26 than the recess 42, and extends from each rib 30 intothe elongated aperture 20 toward the needle 22. In some embodiments,each projection 54 extends only partially into the elongated aperture20. In other words, the projection 54 does not extend far enough tointerfere or substantially interfere with movement of the needle 22.Rather, the projection 54 only extends to a position where it can blockthe cannula 14 from inadvertent movement off of the needle 22.Accordingly, the projection 54 prevents the cannula 14 from disengagingthe needle 22 while the needle 22 is in the retracted position, and yetallows the cannula 14 to be moved past the projection 54 as the slide 18is moved from the retracted position to the extended position.

A locking mechanism 56 can be positioned at the end 48 of each arm 26.The locking mechanism 56 can engage the slide 18 in the extendedposition and prevent the slide 18 from inadvertently returning to theretracted position. The locking mechanism 56 in the illustratedembodiment includes a projection 58 that extends from each arm 26 intothe elongated aperture 20. These projections 58 are positioned anddimensioned to engage a portion of the slide 18 when the slide 18 ismoved to the extended position. Specifically, the projections 58 eachengage a respective recess 60 of the slide 18 to lock the slide 18 inthe extended position. Accordingly, such engagement prevents movement ofthe slide 18 away from the extended position. Dependent at least in partupon the shape of the projections 58 and recesses 60, this engagementcan prevent movement of the slide 18 back toward the retracted positionand/or movement of the slide 18 further away from the retracted position(e.g., out of the elongated aperture 20). For example, none of theprojections 58 and recesses 60 illustrated in the embodiment of FIGS.1-4 have ramped surfaces. Therefore, the slide 18 illustrated in FIGS.1-4 resists movement in either direction from the extended position oncethe projections 58 are engaged within the recesses 60.

As described above, the slide 18 is movable along the arms 26 between aretracted position and an extended position. The slide 18 is movablebetween these positions by sliding along the ribs 30 of the handle 16.As shown in FIG. 4, the slide 18 can have a main channel 62 that extendsalong each side of the slide 18 to receive the ribs 30 of the handle 16.The main channel 62 can be partially defined by upper and lower innersurfaces 64, 66 of the slide 18, as well as an interruptedlongitudinally extending wall 68. The rib 30 is generally receivedwithin this area of the slide 18.

In some embodiments, one or more projections 70 extend from the upperand/or lower inner surfaces 64, 66 of the channel 62. In the illustratedembodiment, for example, a pair of projections 70 extend from each innersurface 64, 66 of the channel 62. These projections 70 can be spacedapart from each other in the longitudinal direction, and can bepositioned and dimensioned to engage the ribs 30 and slide along theribs 30. These projections reduce the amount of surface contact betweenthe upper and lower inner surfaces 64, 66 of the channel 62 and the ribs30, which can therefore reduce the sliding friction between the slide 18and the ribs 30.

As discussed above, projections 46 also extend from the longitudinallyextending surface 68 of the main channel 62. These projections 46 can bepositioned near one end of the main channel 62 and extend in atransverse direction from the longitudinal surface 68 of the mainchannel 62. The projections 46 are dimensioned and positioned to engagethe recesses 40 of the ribs 30 in the retracted position of the slide 18as described above. Accordingly, the slide 18 can be held in theretracted position due to the engagement of the projections 46 with therecesses 40. The projections 46 can also have ramped surfaces 72.Engagement of the ramped surfaces 72 on the projections 46 and theramped surfaces 52 on the recesses 40 allow the slide 18 to be forcedfrom the retracted position to the extended position. In otherembodiments, fewer ramped surfaces (e.g., ramped surfaces 72 only on theprojections 46 or ramped surfaces 52 only on the recesses 40) can beused while still enabling movement of the slide 18 from the retractedposition.

In some embodiments, an additional channel 74 extends along the slide 18in the longitudinal direction. This channel 74 can be recessed into themain channel 62, and can be dimensioned and positioned to receive theprojection 54 as the slide 18 is moved from the retracted position tothe extended position.

As previously discussed, several recesses 60 can be positioned in theslide 18 for engagement with projections 58 of the handle 16 (adjacentthe main channel 62 in the illustrated embodiment). The recesses 60 canbe located on the outside surface of the slide 18 and are dimensionedand positioned to receive the projections 58 of the locking mechanism 56when the slide 18 is in the extended position. In some embodiments, theslide 18 has one or more tapered surfaces 76 extending toward eachrecess 60. These tapered surfaces 76 can initiate engagement between therecesses 60 and the projections 58 of the locking mechanism 56. Thetapered surfaces 76 can provide a transition that causes the arms 26 ofthe handle 16 to elastically expand until the recesses 60 receive theprojections 58 of the locking mechanism 56. In this regard, theprojections 58 elastically move into engagement with the recesses 60 toform an interlocking engagement between the slide 18 and the handle 16.

The needle 22 in the illustrated embodiment has a cylindrical shaft anda pointed tip, and extends from the end of the slide 18. The needle 22can be coupled to the slide 18 in a number of different manners. Forexample, the needle 22 can be insert molded, press fit, or threaded uponor in the slide 18, can be attached to the slide by adhesive or cohesivebonding material, and the like. The needle 22 can move with the slide 18between the retracted position and the extended position. When the slide18 is in the retracted position, the needle 22 is stored within theperiphery of the handle 16, thereby protecting the needle 22. When theslide 18 is moved to the extended position, the needle 22 extends beyondthe periphery of the handle 16.

In some embodiments of the present invention, the trocar-cannulaassembly 10 is assembled as follows. The needle 22 is coupled the slide18, and the slide 18 is coupled the handle 16. The cannula 14 is alsopositioned on the shaft of the needle 22. The slide 18 is placed in theretracted position, where the engagement between the recesses 40 of theribs 30 and the projections 46 of the slide 18 prevent inadvertentmovement of the slide 18 from the retracted position. The slide 18remains in the retracted position until the assembly 10 is ready to beused. Accordingly, the needle 22 is protected against damage.Furthermore, the cannula 14 is blocked from removal by the projection(s)54 when the needle 22 is in the retracted position. Thus, the cannula 14cannot be inadvertently disengaged from the trocar 12 while the needle22 is in the retracted position.

During use of the trocar-cannula assembly 10 illustrated in FIGS. 1-4,the slide 18 is moved from the retracted position to the extendedposition by applying force to the slide 18 relative to the handle 16.Once sufficient force is applied to the slide 18, the ramped surfaces52, 72 of the projections 46 on the slide and the recesses 40 in theribs 30 begin to move relative to each other. This causes the arms 26 ofthe handle 16 to elastically expand, thereby allowing the projections 46to disengage the recesses 40. Once the projections 46 disengage therecesses 40, the slide 18 can be moved toward the extended position. Asthe projections 46 of the slide 18 move past the projections 44 on eachrib 30, the projections 46 of the slide 18 move along another rampedsurface 50. This allows the arms 26 to elastically return to anon-biased position. Once the projections 46 on the slide 18 pass theseprojections 44 on the ribs 30, the slide 18 can move to the extendedposition relatively easily. As the slide 18 moves to the extendedposition, the needle 22 begins to extend from the periphery of thehandle 16.

To use the trocar 12 to insert the cannula 14, the needle 22 and slide18 are locked with respect to one another in the extended position. Theslide 18 is locked in the extended position as the slide 18 is moved tothe extended position. During this movement, the tapered end 76 of theslide 18 adjacent the needle 22 engages the projections 56 at the end 48of each arm 26. The engagement of the tapered surfaces 76 with theprojections 58 causes the arms 26 to move away from one another untilthe recesses 60 in the slide 18 align with the interlocking projection58 of each arm 26. Upon alignment of these features, the arms 26 urgethe projections 58 into the recesses 60. This interlocking relationshipprevents relative movement between the slide 18 and the handle 16.

During insertion of the cannula 14 into an eye, the pointed tip of theneedle 22 punctures the surface of the eye. The handle 16 of the trocar12 is then pressed forward to further drive the needle 22 into the eye.As the needle 22 is further inserted into the eye, a portion of thecannula 14 is inserted into the puncture. The needle 22 can then bewithdrawn from the eye to leave the cannula 14 retained in the eye. Theforces of the elastically deformed tissues surrounding the puncture canhelp to retain the cannula 14 in the eye.

The embodiments described above and illustrated in the figures arepresented by way of example only and are not intended as a limitationupon the concepts and principles of the present invention. As such, itwill be appreciated by one having ordinary skill in the art that variouschanges in the elements and their configuration and arrangement arepossible without departing from the spirit and scope of the presentinvention. For example, the interlocking features of the slide 18 andthe ribs 30 are described with respect to a specific construction usingprojections engagable within recesses. Specifically, in some positionsof the slide 18, a projection from the slide 18 or handle 16 isdescribed as engaging a recess in the handle 16 or slide 18,respectively. In alternative embodiments, these interlocking engagementscan be reversed.

As another example, the handle 16 described above and illustrated in thefigures has a pair of arms 26 between which the slide 18 moves. Amongother functions, the arms 26 serve to protect the needle 22 prior to useof the assembly 10. In other embodiments, the handle 16 can have othershapes in which the needle 22 is protected prior to use, some of whichdo not have a pair of arms 26 as described above. For example, theneedle 22 and slide 18 can be received within a tubular element, wherebya portion of the slide 18 extends through an elongated aperture in thehandle 16 and can be manipulated by a user to extend and retract theslide 18 as described above. As another example, the needle 22 and slide18 can be received within a channel of a handle 16, whereby the slide 18is accessible by a user to move the slide 18 to an extended position asdescribed above. In such alternative embodiments, the handle 16 andslide 18 can still have any or all of the other features and elementsdescribed above with respect to the illustrated embodiment (e.g.,projections 44, 58, 54, recesses 40, 42, 60, and the like).

As yet another example, the slide 18 illustrated in FIGS. 1-4 isslidable engaged with two arms 26. In other embodiments, the slide 18can instead be slidably engaged with only one of the two arms 26, or canbe slidably engaged with a handle having a single arm 26 and one or moreother handle portions shielding the needle 22 when in the retractedposition.

As described above, the ophthalmic trocar-cannula assembly 10 has ahandle 16. It should be noted that the term “handle” does not indicateor imply that the ophthalmic trocar-cannula assembly 10 is restrictedfor use and manipulation by a human hand. The ophthalmic trocar-cannulaassembly 10 can be mounted to any element or structure for manipulationin any other manner, such as by a robotic arm or other equipment.

Various features of the invention are set forth in the following claims.

1. An ophthalmic trocar comprising: a handle having a top surface and abottom surface, the handle including a body portion; a pair of armsextending from the body portion in a longitudinal direction, the arms atleast partially defining a longitudinally extending aperture; and a ribon each arm; a slide positioned between the pair of arms and movablealong the ribs in the longitudinal direction between a retractedposition and an extended position; and a needle coupled to the slide andmovable along with the slide between the retracted position and theextended position, the needle positioned substantially entirely withinan outer periphery of the handle in the retracted position, at least aportion of the needle extending beyond the periphery of the handle inthe extended position.
 2. The ophthalmic trocar of claim 1, wherein theslide is interlocked with the rib in the retracted position of the slideto retain the slide in the retracted position.
 3. The ophthalmic trocarof claim 2, wherein the slide has a projection releasably engagable witha recess in the rib to retain the slide in the retracted position. 4.The ophthalmic trocar of claim 3, wherein at least one of the projectionand recess has a ramped surface to allow movement of the slide out ofthe retracted position by movement of the arms.
 5. The ophthalmic trocarof claim 1, further comprising a projection extending from the handleinto the elongated aperture, the projection positioned to block removalof a cannula positioned on the needle when the slide is in the retractedposition.
 6. The ophthalmic trocar of claim 1, wherein the slide isinterlocked with the handle in the extended position of the slide toretain the slide in the extended position.
 7. The ophthalmic trocar ofclaim 6, further comprising a projection extending from each arm intoengagement with a respective recess on the slide when the slide is inthe extended position.
 8. The ophthalmic trocar of claim 7, wherein theslide is interlocked with the rib in the retracted position of the slideto retain the slide in the retracted position.
 9. The ophthalmic trocarof claim 8, further comprising a projection extending from the slideinto engagement with a recess on the handle when the slide is in theretracted position.
 10. The ophthalmic trocar of claim 9, wherein thearms are elastically deformable to release the slide from the retractedposition.
 11. A method of inserting a ophthalmic cannula into aneyeball, the method comprising: providing a trocar having a cannulapositioned on a needle of the trocar; sliding the needle from aretracted position to an extended position relative to a handle of thetrocar, the needle being substantially entirely contained within aperiphery of the handle in the retracted position, at least a portion ofthe needle extending beyond the periphery of the handle in the extendedposition; retaining the needle in the extended position; and insertingthe needle and the cannula into an eyeball.
 12. The method of claim 11,further comprising resisting movement of the needle from the retractedposition to the extended position with an interlocking engagementbetween a slide coupled to the needle and the handle.
 13. The method ofclaim 12, wherein sliding the needle from the retracted position to theextended position further comprises forcing the slide to disengage theinterlocking engagement.
 14. The method of claim 13, wherein forcing theslide includes forcing a portion of the slide against a portion of thehandle to cause a part of the handle to elastically deform until theslide is disengaged from the interlocking engagement.
 15. The method ofclaim 11, wherein locking the needle in the extended position comprisesestablishing an interlocking engagement between a slide coupled to theneedle and the handle.
 16. The method of claim 15, further comprisingdriving a ramped surface of the slide against the handle to elasticallyexpand a portion of the handle.
 17. The method of claim 11, furthercomprising blocking the cannula from removal from the needle with aprojection extending from the handle while the needle is in theretracted position.
 18. A surgical instrument comprising: a trocarincluding a handle having an outer periphery and a projection extendingfrom the handle; a slide coupled to the handle for sliding movementrelative to the handle; and a needle coupled to the slide and movablewith the slide between an extended position and a retracted position,the needle contained substantially entirely within the outer peripheryof the handle when in the retracted position, at least part of theneedle extending from the outer periphery of the handle in the extendedposition; and a cannula positioned on the needle, the projectionextending to a position in which the projection blocks removal of thecannula from the needle when the needle is in the retracted position.19. The surgical instrument of claim 18, wherein the handle has anelongated aperture and the slide moves within the elongated aperture toplace the needle in the extended and retracted positions.
 20. Thesurgical instrument of claim 19, wherein the projection extends into theelongated aperture.
 21. The surgical instrument of claim 19, furthercomprising a first interlocking engagement between the handle and theslide, the first interlocking engagement preventing movement of theslide relative to the handle to retain the needle in the retractedposition.
 22. The surgical instrument of claim 21, wherein the slide canbe forced relative to the handle to disengage the slide from the firstinterlocking engagement by elastically deforming a portion of thehandle.
 23. The surgical instrument of claim 21, further comprising asecond interlocking engagement between the handle and the slide, thesecond interlocking engagement preventing movement of the slide relativeto the handle to retain the needle in the extended position.